#!/usr/bin/perl

# Copyright © 2022 Felix Lechner <felix.lechner@lease-up.com>
#
# based on a shell script by the same name
#     by Arjan Oosting <arjan@debian.org>
#     and Joachim Breitner <nomeata@debian.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

use v5.20;
use warnings;
use utf8;

use Const::Fast;
use List::SomeUtils qw(none uniq);
use Path::Tiny;
use Unicode::UTF8 qw(encode_utf8);

use Debian::Debhelper::Buildsystem::Haskell::Recipes qw(
  run
  init_hs_env
  installable_type
  installable_hc
  installable_config_shipper
  hc_pkgdir
  ghc_pkg_command
  load_ghc_database
  hashed_id_to_virtual_installable
  config_to_package_id
);
use Debian::Debhelper::Dh_Lib;

const my $SPACE => q{ };
const my $COMMA => q{,};
const my $NEWLINE => qq{\n};

init(
    options => {
        'config-shipper=s' => \$dh{CONFIG_SHIPPER},
    });
init_hs_env();

for my $installable (@{ $dh{DOPACKAGES} }) {

    my $compiler = installable_hc($installable) || $ENV{DEB_DEFAULT_COMPILER};
    my $pkgdir = hc_pkgdir($compiler);

    my $config_shipper
        = $dh{CONFIG_SHIPPER} || installable_config_shipper($installable);
    my $confdir = "debian/$config_shipper/$pkgdir";

    my @configs;
    @configs = grep { $_->is_file } path($confdir)->children(qr{ [.]conf $}x)
      if -e $confdir;

    unless (@configs) {

        warn encode_utf8('No Haskell package description are being shipped.');
        next;
    }

    my $ghc_pkg = ghc_pkg_command();
    load_ghc_database($ghc_pkg, $ENV{DEB_GHC_DATABASE}, @configs);

    my @hashed_ids;
    for my $config (@configs) {
        my $package_id = config_to_package_id($config, $ghc_pkg, $ENV{DEB_GHC_DATABASE});
        push(@hashed_ids, $package_id);
    }

    my $substvars_path = "debian/$installable.substvars";

    my $type = installable_type($installable);
    if ($type eq 'dev') {
        replace_line($substvars_path, "haskell:$compiler-package",
            join($SPACE, @hashed_ids));
    }

    my @provides = map {
        hashed_id_to_virtual_installable($compiler, $_, $type,
            $ghc_pkg, '--package-db', $ENV{DEB_GHC_DATABASE})
    } @hashed_ids;

    # fix sort order
    local $ENV{LC_ALL} = 'C.UTF-8';

    replace_line($substvars_path, 'haskell:Provides',
        join($COMMA . $SPACE, (sort +uniq @provides)));
}

exit;

sub replace_line {
    my ($path, $field, $value) = @_;

    path($path)->touch;

    my @lines = grep { !m{^ $field = }x } path($path)->lines_utf8;

    push(@lines, "$field=$value" . $NEWLINE);

    path($path)->spew_utf8(@lines);

    return;
}

=head1 NAME

dh_haskell_provides_ghc - calculates Haskell virtual package names on Cabalized libraries

=head1 SYNOPSIS

B<dh_haskell_provides_ghc> [S<I<debhelper options>>]
[B<-X>I<package>]
[B<--exclude=>I<package>]
[S<I<file>> ...]

=head1 DESCRIPTION

dh_haskell_provides_ghc is a debhelper program that calculates the correct virtual
package to provide, so that dependencies can guarantee ABI stability.

For a package with an idea of package-version-longhashstring, it generates a
virtual package of the form libghc-package-dev-version-longh for the -dev
package and libghc-package-prof-version-longh for the prof package
respectively.

This script writes the debian/$package.substvars file, including in it the
haskell:Provides.  So, to use this package, include in the Provides: field in
debian/control ${haskell:Provides}.

=head1 SEE ALSO

L<dh_haskell_depends(1)>
L<dh_haskell_shlibdeps(1)>
L<debhelper(7)>

=head1 AUTHOR

Joachim Breitner <nomeata@debian.org>

Based on ideas in dh_ocaml.

=cut

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